A number of power supplies have been proposed for electronic flash purposes where the circuit, operating from a power source, functions with means for charging and discharging a capacitor for operating a flash lamp. Typically, many of the systems have had means of some type for sensing the capacitor voltage and disabling the charging circuit after the capacitor has been fully charged, to save power.
The prior art systems mentioned above generally have limitations which make them not suitable for use with toy weapons which require an immediate bright flash in response to trigger actuation, rapid recharging to afford as much realism as possible for children playing with such toys, and relative light weight. These prior systems typically have a relatively long charging time, betwen 6 and 30 seconds, or have relatively large sources of power, such as large or bulky batteries, or are connected to an AC source and are thereby non-portable. Also these systems, in order to achieve the desired results, are frequently quite complex as well as being too large to be employed in a children's toy. Another problem with many prior art systems is that the voltage sensing mechanism is not precise so there is a relatively large swing between full charge of the flash capacitor and the voltage level at which the charge again builds up. They often use a linear technology or a flyback transformer in the feedback circuit.